CN109694735B

CN109694735B - Hydrogenation dechlorination method for alkylate oil

Info

Publication number: CN109694735B
Application number: CN201710985505.1A
Authority: CN
Inventors: 徐大海; 关明华; 丁贺; 李扬; 牛世坤; 李士才; 陈�光
Original assignee: China Petroleum and Chemical Corp; Sinopec Dalian Research Institute of Petroleum and Petrochemicals
Current assignee: Sinopec Dalian Petrochemical Research Institute Co ltd; China Petroleum and Chemical Corp
Priority date: 2017-10-20
Filing date: 2017-10-20
Publication date: 2020-11-10
Anticipated expiration: 2037-10-20
Also published as: CN109694735A

Abstract

The invention discloses a hydrodechlorination method for alkylate oil. The method comprises the following steps: after the alkylation reaction is finished, separating out the ionic liquid catalyst, and sequentially carrying out hydrodechlorination, adsorption and HCl removal on the alkylation mixed product and rectification in a rectifying tower; during start-up, an alkylation mixed product firstly enters a rectifying tower for rectification, then a tower bottom material of the rectifying tower is introduced into a hydrodechlorination reactor for hydrodechlorination, then is adsorbed by an adsorption and dechlorination device, and is introduced into the rectifying tower for 5 minutes to 24 hours after adsorption is completed, the alkylation mixed product is stopped being directly introduced into the rectifying tower, the tower bottom material of the rectifying tower is stopped being introduced into the hydrodechlorination reactor, the alkylation mixed product is started to be directly introduced into the hydrodechlorination reactor, and a normal hydrodechlorination reaction process is carried out. The method can ensure that the chlorine content of the alkylate oil with high chloride ion is reduced to below 1ppm after the alkylate oil with high chloride ion is treated, and the alkylate oil can be used as a blending component of high-quality motor gasoline.

Description

Hydrogenation dechlorination method for alkylate oil

Technical Field

The present invention relates to a hydrodechlorination method for alkylate, particularly to a method for dechlorinating alkylate with high chlorine content by hydrogenation and dechlorination treatment, which is particularly suitable for the produced oil of an ionic liquid alkylation process.

Background

The alkylate oil is a common gasoline blending component with high octane number, has the characteristics of high octane number, good anti-knock performance, low vapor pressure, low sulfur content, no olefin or aromatic hydrocarbon and the like, and is an ideal clean gasoline blending component. Alkylate is typically produced by reacting isobutane with an olefin over an acid catalyst. The alkylate oil has many technical types, and can be divided into two main types of liquid acid alkylation and solid acid alkylation according to the phase state of the catalyst. The liquid acid alkylation technology comprises three types of hydrofluoric acid, sulfuric acid and ionic acid; the solid acid is mainly a special zeolite catalyst.

Currently, liquid acid alkylation processes are the most common processes, with ionic liquid alkylation being the most recently developed alkylation process technology. The ionic liquid has the advantages of non-volatility, nearly zero vapor pressure, non-combustibility, high thermal stability, wide temperature range of liquid existence and the like, and is known to be an environment-friendly system; in recent years, the compound has attracted much attention because of having both high-density reactivity of liquid acid and non-volatility of solid acid. Companies such as CHEVRON, SHELL and petroleum university and colleges have conducted a great deal of research work on ionic liquid alkylation technology. The ionic liquid alkylation technology developed by the university of petroleum was built and put into production in 9 months in 2013 at chemical Limited, Deyang, Shandong.

The ionic liquid catalytic alkylation process comprises three parts of raw material pretreatment, alkylation reaction and product separation, and ionic liquid regeneration. The main active component of the ionic liquid is aluminum chloride, and the cation part comprises Cu ions and the like, so that the alkylation produced oil contains chloride ions or chlorinated hydrocarbons, and the chloride ions have strong corrosivity, so that the ionic liquid has great hidden danger on the safe use of parts such as automobile fuel tanks, engines and the like, and can be used as a vehicle gasoline blending component only by being removed.

At present, dechlorination of alkylate produced by chain reaction of isobutane and olefin is less studied, and adsorption removal method is mainly adopted. For example, CN204918487U discloses an alkylate dechlorination apparatus comprising a dechlorination unit a and a dechlorination unit B. The chlorinated alkylate oil conveyed from the reaction device enters a dechlorinating device filled with dechlorinating agent through a material inlet of the dechlorinating device through a raw material pipeline, and residual organic chlorine carried by the chlorinated alkylate oil is adsorbed into the dechlorinating agent when the chlorinated alkylate oil passes through the dechlorinating agent in the dechlorinating device. Discharging the qualified alkylate oil after organic chloride removal from a material outlet of a dechlorination device, and feeding the alkylate oil into an alkylate oil product tank. After dechlorination, the total chlorine content in the alkylate oil is reduced to below 1ppm, and the requirements of the market on the quality of oil products are met. But is limited by the organic chlorine adsorption capacity of the solid adsorbent, and requires frequent regeneration, increasing the difficulty and cost of operation of the process.

In addition to the adsorption removal method, a hydrogenation removal method may be employed. For example, CN106995720A discloses a liquid phase dechlorination method for chlorinated alkylate, which comprises the following steps: (1) liquid-phase hydrogenation: under the condition of hydrogenation, the chlorinated alkylate oil reacts with hydrogen and a hydrogenation catalyst in a liquid phase state to generate a hydrogenation product containing HCl; (2) liquid phase adsorption: contacting the hydrogenation product containing HCl with an adsorbent in a liquid phase state, and adsorbing HCl to obtain the hydrogenation product after HCl removal: (3) oil-gas separation: and separating the hydrogenation product after HCl removal from hydrogen to obtain dechlorinated alkylate oil. The liquid-phase dechlorination method adopts liquid-phase hydrogenation, has mild operation conditions and low hydrogen-oil ratio, does not need equipment such as a hydrogenation feeding heating furnace and the like, and can realize the complete conversion of organic chlorine. However, since the HCl-containing hydrogenated product is contacted with the adsorbent in a liquid phase, the diffusion rate of HCl in the liquid phase is slow, and the HCl content in the hydrogenated product is low (not more than 500 ppm), which results in a very long adsorption residence time to remove most of HCl, thereby affecting the dechlorination efficiency of the alkylate.

CN103025687A discloses the hydrodechlorination of ionic liquid derived hydrocarbon products. The process hydrodechlorinates one or more hydrocarbon products from an ionic liquid catalyzed hydrocarbon conversion reaction to provide a dechlorinated product and an HCl-containing off-gas, the resulting dechlorinated product having a chloride content of less than 50ppm, typically less than 10 ppm. Although the method can also achieve the aim of dechlorination, the process needs gas-liquid separation, and HCl and H are generated after separation₂、C₁-C₅Hydrocarbon off-gases, and further recovery or separation of HCl is also required. The whole process flow is relatively complex, and the investment and operation cost is relatively high.

In addition, in the process of starting up the hydrodechlorination device, the reaction conditions and the catalyst performance do not reach the required state of the reaction, so the hydrodechlorination product generally does not reach the quality index.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a hydrodechlorination method for alkylate. The method can not only meet the requirement that the chlorine content of the alkylate oil meets the blending component of the motor gasoline, but also improve the dechlorination efficiency, and simultaneously solve the problem that the product quality does not reach the standard in the initial startup period of the hydrodechlorination device.

The invention provides a hydrodechlorination method for alkylate, which comprises the following steps: separating the ionic liquid catalyst after the alkylation reaction is finished to obtain an alkylation mixed product, directly feeding the alkylation mixed product into a hydrodechlorination reactor, then carrying out hydrodechlorination to generate a hydrogenated product containing HCl, feeding the hydrogenated product into an adsorption dechlorination device to adsorb the HCl in the hydrogenated product, and feeding the hydrogenated product into a rectifying tower to be rectified after the adsorption is finished;

when a hydrodechlorination reactor is started, an alkylation mixed product firstly enters a rectifying tower for rectification, then a material at the bottom of the rectifying tower is introduced into the hydrodechlorination reactor for hydrodechlorination, then is adsorbed by an adsorption dechlorination device, and is introduced into the rectifying tower for 5 minutes to 24 hours, preferably 1 to 10 hours, after adsorption is completed, the alkylation mixed product is stopped from being directly introduced into the rectifying tower, the material at the bottom of the rectifying tower is stopped from being introduced into the hydrodechlorination reactor, the alkylation mixed product is directly introduced into the hydrodechlorination reactor, and a normal hydrodechlorination reaction process is carried out.

In the process of the present invention, the hydrodechlorination is carried out in a liquid phase reaction state, i.e., at least a portion of the alkylation product mixture (alkylate) is in a liquid phase under the reaction conditions.

In the method, a tower bottom reboiler arranged on the rectifying tower provides a heat source for the rectifying tower, the rectifying tower bottom material introduced into the hydrodechlorination reactor is led out after the tower bottom reboiler, and preferably, the temperature of the rectifying tower bottom material led out after the tower bottom reboiler is 100-200 ℃.

In the method, a material conveying device is arranged at the bottom of the rectifying tower, and the material at the bottom outlet of the rectifying tower is conveyed to a pipeline in front of the inlet of the hydrodechlorination reactor through the material conveying device.

In the method, a heat exchanger and a gas-liquid mixer are sequentially arranged on a pipeline before entering a hydrodechlorination reactor, the heat exchanger is used for heating an alkylation mixed product, the gas-liquid mixer is used for fully mixing hydrogen and the alkylation mixed product, the gas-liquid mixer is preferably a static mixer or a dynamic mixer, the static mixer is selected from one or a combination of a SV type static mixer, an SK type static mixer, an SX type static mixer, an SH type static mixer and an SL type static mixer, and the dynamic mixer is selected from one or a combination of a mixing pump, a supercritical mixer and a stirring mixer.

In the method, a first valve is arranged on a pipeline in front of a gas-liquid mixer.

In the method, a first pipeline for connecting the tower bottom material of the rectifying tower and the inlet of the heat exchanger is arranged, and a second valve is arranged on the first pipeline.

In the method, a second pipeline is arranged for connecting the inlet of the rectifying tower and the pipeline in front of the first valve, and the second pipeline is provided with a third valve.

In the method, a third pipeline is arranged for connecting an isobutane outlet of the rectifying tower and an inlet of the first gas-liquid mixer, and a fourth valve is arranged on the third pipeline.

In the method, the reaction conditions of hydrodechlorination are as follows: the reaction pressure is 0.5MPa to 6.0MPa, preferably 1.2MPa to 3.0 MPa; the reaction temperature is 100-200 ℃, and preferably 120-170 ℃; the volume space velocity is 1.0 h^-1～10. 0h^-1Preferably 2.0 h^-1～6.0 h^-1(ii) a The volume ratio of hydrogen to oil is 50: 1 or less, preferably 2: 1-10: 1.

in the method, the used hydrodechlorination catalyst can be a commercial hydrodechlorination catalyst, preferably a hydrodechlorination catalyst taking noble metal as an active component, and the noble metal hydrodechlorination catalyst generally takes alumina as a carrier, such as an FHDA-10 catalyst developed and produced by the Fushun petrochemical research institute. Preferably, Pt and/or Pd are used as active components, the content of active components in the catalyst is not less than 0.1% by weight, generally 0.1% to 1.5% by weight. For the alkylate oil raw material, the organic chloride in the alkylate oil generated by the alkylation can be reduced to below 1ppm by using the hydrodechlorination catalyst, and the requirements of high-quality automobile gasoline blending components are met.

In the method of the present invention, the adsorption dechlorination apparatus may be filled with a conventional industrial dechlorinating agent, which is an oxide of an alkaline earth metal, preferably calcium oxide and/or magnesium oxide.

In the method, the operation conditions of the adsorption dechlorination device are as follows: the adsorption pressure can be the same as or different from the temperature and the pressure of the hydrodechlorination reactor, the adsorption temperature is 100-200 ℃, the adsorption pressure is 0.5-6.0 MPa, and the preferred pressure is 1.2-3.0 MPa.

In the method, at the initial stage of start-up, part of the tower bottom materials of the rectifying tower are thrown outwards to obtain the dechlorinated alkylate oil.

In the method, the hydrodechlorination reactor adopts an up-flow operation mode, namely, reaction materials enter the reactor from the lower part of the hydrodechlorination reactor to carry out hydrodechlorination reaction, and refined oil can directly enter a gasoline pool after passing through a separator. The hydrodechlorination reactor can also adopt a downflow operation mode, namely the reaction materials enter the reactor from the top of the hydrodechlorination reactor to carry out the hydrodechlorination reaction.

In the method, the alkylation reaction is an alkylation reaction adopting an ionic liquid catalyst, isobutane is usually excessive in the reaction process, and the molar ratio of isobutane to butene is preferably (2-40): 1, more preferably (5-20): 1. the reaction temperature can be determined to be-20-100 ℃, and is generally 0-50 ℃; the reaction pressure should be selected to ensure that the reaction raw materials are kept in a liquid state under the reaction condition as a lower limit, and can be generally 0.1-1.6 MPa.

Compared with the prior art, the invention has the following beneficial technical effects:

(1) according to the method, the alkylation mixed product is directly subjected to hydrodechlorination without separation to generate a hydrogenated product containing HCl, and the hydrogenated product containing HCl is subjected to hydrodechlorinationAdsorbing by an adsorption dechlorination device, and introducing into a rectifying tower for rectifying after adsorption; in this way, unreacted gases such as isobutane and n-butane in the alkylated mixed product can be stripped from the liquid phase, so that the HCl can be quickly diffused and adsorbed when being adsorbed by an adsorbent in an adsorption dechlorination device, and the HCl removal efficiency of the hydrogenated product is improved. In addition, the alkylation mixed product is subjected to hydrodechlorination and adsorption dechlorination, and then gases such as isobutane, normal butane and hydrogen are separated by rectification, so that HCl and H are not generated after dechlorination₂、C₁-C₅Hydrocarbon off-gas.

In the initial start-up period, the alkylated mixed product firstly enters the rectifying tower for rectification, then the tower bottom material of the rectifying tower is introduced into the hydrodechlorination reactor for hydrodechlorination, and then enters the rectifying tower again through the adsorption dechlorination device, so that the product quality requirement in the initial period can be ensured, the unqualified stabilization period of the product can be avoided, the alkylated mixed product can be quickly heated by using the tower bottom reboiler of the rectifying tower to reach the temperature requirement of the hydrodechlorination, an additional heater is not needed, the defects of instability and slow heating of the heat exchanger in the initial start-up period are overcome, and the subsequent normal hydrogenation reaction process is not influenced.

(2) The method of the invention fully utilizes the characteristics of low temperature and high hydrogenation activity of the noble metal hydrogenation catalyst, adopts the process flow of feeding, hydrogenation and dechlorination under liquid phase, reduces the investment cost, can realize the requirement that high-chlorine alkylation is directly used as the blending component of the motor gasoline, and the dechlorinated generated oil directly enters the motor gasoline pool without further treatment to be delivered as a qualified product.

(3) For the alkylation device of the oil refining enterprise, only a hydrodechlorination reactor and an adsorption dechlorination device are needed to be added between a settling tower and a rectifying tower of the alkylation device, and a set of hydrodechlorination device does not need to be newly built independently, so that the process flow is simple, the operation conditions are mild, the practicability is high, and the investment and the operation cost can be greatly reduced.

Drawings

FIG. 1 is a schematic representation of the hydrodechlorination of alkylate of the present invention;

wherein: the method comprises the following steps of 1-isobutane tank, 2-butene tank, 3-ion liquid tank, 4-first gas-liquid mixer, 5-alkylation reactor, 6-settling tank, 7-heat exchanger, 8-second gas-liquid mixer, 9-make-up hydrogen compressor, 10-hydrodechlorination reactor, 11-first adsorption dechlorination device, 12-second adsorption dechlorination device, 13-rectifying tower, 14-reboiler, 15-first valve, 16-second valve, 17-third valve and 18-fourth valve.

Detailed Description

The method of the present invention is described in detail below with reference to the accompanying drawings and specific examples.

For a newly built apparatus using the method of the present invention, as shown in FIG. 1: after the alkylation device and the hydrogenation device are started, introducing isobutane in an isobutane tank 1 and butene in a butene tank 2 into a first gas-liquid mixer 4, then mixing the isobutane and the butene in an ionic liquid tank 3, then introducing the mixture into an alkylation reactor 5, after the reaction is finished, introducing the mixture into a settling tank 6, settling and separating out ionic liquid and an alkylated mixed product, closing a first valve 15, opening a third valve 17, directly introducing the alkylated mixed product into a rectifying tower 13, introducing the alkylated mixed product into a reboiler 14 through a bottom pump of the rectifying tower 13, heating the alkylated mixed product to a temperature required by the reaction, opening a second valve 16, selectively opening a fourth valve 18, returning the heated material to a heat exchanger 7, then fully mixing the alkylated mixed product with isobutane and hydrogen-rich gas 5 conveyed by a supplementary hydrogen compressor 9 in a second gas-liquid mixer 8, introducing the mixed product from the bottom of a hydrogenation dechlorination reactor 10, and contacting with a noble metal hydrogenation catalyst, carrying out hydrodechlorination reaction under the condition of hydrodechlorination to convert organic chloride in the alkylate oil into inorganic chloride, after the reaction is finished, enabling a product containing isobutane, hydrogen and HCl to enter a first adsorption dechlorination device 11 to adsorb and remove inorganic chloride (HCl), enabling the dechlorinated product to enter a rectifying tower 13 again to be rectified, obtaining dechlorinated alkylate oil at the bottom of the tower, obtaining normal butane at the middle part, obtaining isobutane at the upper part and obtaining other gases at the top part. The dechlorinated alkylate oil obtained at the bottom of the tower can be totally or partially fed into a hydrodechlorination reactor 10, and when the alkylate oil is discharged from the outside of the bottom of the tower, dechlorinated alkylate oil at the initial startup stage can be obtained and can be directly used as a gasoline blending component or further dechlorinated.

When the hydrodechlorination reactor 10 enters a normal working condition, the second valve 16, the third valve 17 and the fourth valve 18 are closed, the first valve 15 is opened, and the hydrodechlorination part enters a normal production process flow. Meanwhile, at the initial startup stage, the rectified isobutane is selectively introduced, so that HCl generated by hydrodechlorination enters isobutane gas, and the isobutane can be rectified by the rectifying tower again, so that an additional device is not needed for separation, and the subsequent normal startup is not influenced.

After the dechlorinating agent in the first adsorption dechlorinating device 11 is saturated, the valve of the first adsorption dechlorinating device 11 is closed, the valve of the second adsorption dechlorinating device 12 is opened, the second adsorption dechlorinating device 12 is entered, and meanwhile, the dechlorinating agent in the first adsorption dechlorinating device 11 is replaced or regenerated, so that the continuous and stable operation of the dechlorinating unit can be ensured.

The dechlorination unit has simple process flow and solves the problem that the alkylate oil can not be directly used as blending components of the motor gasoline. The alkylation oil treated by the method of the invention can achieve the following properties: the chlorine content of the refined oil is less than 1 ppm. Other properties meet the requirements of blending components of high-quality motor gasoline.

The following examples further illustrate the invention.

The catalyst used in the experiment is a hydrodechlorination catalyst applied to industry, and the index of the physicochemical property of the FHDA-10 hydrogenation catalyst developed and produced by the smooth petrochemical research institute is shown in Table 1.

TABLE 1 index of physicochemical Properties of the catalyst

Catalyst numbering	FHDA-10
		Metal composition	Pt-Pd
Physical Properties
		Pore volume, mL/g	≮0.45
Specific surface area, m²/g	≮170
		Compressive strength, N/cm	≮90
Shape of	Cylindrical bar shape

Example 1

The alkylation device is newly built according to the scheme of the invention. After the alkylation reaction is finished, ionic liquid is separated through a settling tank 6, and then the ionic liquid and hydrogen are fully mixed and dissolved in an SX type static mixer through a feeding pump and a heat exchanger 7, and then the mixture enters a hydrodechlorination reactor 10, wherein the reaction conditions are as follows: the reaction pressure is 1.5MPa, and the liquid hourly space velocity is 3.8h^-1And a reaction temperature of 143 ℃. After the reaction is finished, the reaction product enters a first adsorption dechlorination device 11 to adsorb and remove inorganic chloride. The first adsorption dechlorinating device 11 is filled with a conventional industrial dechlorinating agent, and the main component of the dechlorinating agent is calcium oxide. The adsorption temperature of the adsorption dechlorination device is 140 ℃, and the adsorption pressure is 1.4 MPa. Then the adsorption dechlorination product enters a rectifying tower 13 for rectification, dechlorinated alkylate oil is obtained at the bottom of the tower, normal butane is obtained at the middle part, isobutane is obtained at the upper part, and other gases are obtained at the top. The properties of alkylate oil in the pre-hydrodechlorination alkylation mixed product and the final product obtained from the rectifying towerThe alkylate properties are listed in Table 2.

When the method is adopted to start the hydrogenation device, firstly, an alkylation mixed product enters a rectifying tower 13 to be rectified, firstly, all the tower bottom materials of the rectifying tower 13 (the temperature of the rectifying tower bottom materials led out after a tower bottom reboiler is 143 ℃) are led into a hydrodechlorination reactor 10, and the rear parts of the tower bottom materials are led into the hydrodechlorination reactor 10, meanwhile, isobutane circulated in the rectifying tower can be selectively led into the hydrodechlorination reactor 10 through a second gas-liquid mixer 8 to be subjected to hydrodechlorination, then the isobutane is adsorbed through a first adsorption dechlorination device 11 or a second adsorption dechlorination device 12, after the adsorbed materials enter the rectifying tower for 5 hours, the tower bottom materials and the isobutane of the rectifying tower 13 are stopped being led in, and the alkylation mixed product is stopped being directly led into the rectifying tower 13, so that the normal operation flow is switched.

As can be seen from Table 2, the chlorine content of the alkylate oil can be reduced to below 1ppm by using the process technology when the hydrodechlorination unit is in normal operation, and the product quality is kept stable in the whole operation process.

Example 2

The alkylation device is newly built according to the scheme of the invention. After the alkylation reaction is finished, ionic liquid is separated through a settling tank 6, and then the ionic liquid and hydrogen are fully mixed and dissolved in an SX type static mixer through a feeding pump and a heat exchanger 7, and then the mixture enters a hydrodechlorination reactor 10, wherein the reaction conditions are as follows: reaction pressure of 1.6MPa and liquid hourly space velocity of 4.2h^-1The reaction temperature was 157 ℃. After the reaction is finished, the reaction product enters a first adsorption dechlorination device 11 to adsorb and remove inorganic chloride. The first adsorption dechlorination device 11 is filled with a conventional industrial dechlorination agent, and the main component of the dechlorination agent is magnesium oxide. The adsorption temperature of the adsorption dechlorination device is 156 ℃, and the adsorption pressure is 1.5 MPa. Then the adsorption dechlorination product enters a rectifying tower 13 for rectification, dechlorinated alkylate oil is obtained at the bottom of the tower, normal butane is obtained at the middle part, isobutane is obtained at the upper part, and other gases are obtained at the top. The properties of the alkylate in the alkylate mixture before hydrodechlorination and the alkylate in the final product obtained in the rectification column are shown in Table 2.

When the method is adopted to start up the hydrogenation device, firstly, an alkylation mixed product enters a rectifying tower 13 to be rectified, firstly, all the tower bottom materials of the rectifying tower 13 (the temperature of the rectifying tower bottom materials led out after a tower bottom reboiler is 157 ℃) are led into a hydrodechlorination reactor 10, and the rear parts of the tower bottom materials are led into the hydrodechlorination reactor 10, meanwhile, circulating isobutane can be selectively led into the hydrodechlorination reactor 10 through a second gas-liquid mixer 8 to be subjected to hydrodechlorination, then the materials are adsorbed through a first adsorption dechlorination device 11 or a second adsorption dechlorination device 12, after the adsorbed materials enter the rectifying tower for 4 hours, the tower bottom materials and the isobutane led into the rectifying tower 13 are stopped, and the alkylation mixed product is stopped being directly led into the rectifying tower 13 to be switched into a normal operation flow.

Comparative example 1

The procedure of example 1 was followed except that the alkylation mixture was fed directly to the hydrogenation reactor at start-up for normal operation. During the start-up, the quality of the hydrogenation reaction product is not up to the standard (more than 10 ppm) in about 30 hours, and more than 50ppm in 5 hours at the initial start-up.

TABLE 2 Properties and test results of hydrodechlorination feedstock

Item	Example 1	Example 2
			Process conditions
Reaction temperature of	143	157
			Reaction pressure, MPa	1.5	1.6
Liquid hourly volume space velocity, h^-1	3.8	4.2
			Oil quality
Chloride content of alkylated oil before hydrodechlorination, ppm	750	579
			Chlorine content of the alkylate oil after dechlorination, ppm at the beginning of start-up	＜10	＜10
Normal operation, chloride content of alkylate after dechlorination, ppm	＜1.0	＜1.0

Claims

1. A hydrodechlorination process for alkylate, comprising the following steps: separating the ionic liquid catalyst after the alkylation reaction is finished to obtain an alkylation mixed product, and is characterized in that the alkylation mixed product directly enters a hydrodechlorination reactor, then is subjected to hydrodechlorination to generate a hydrogenated product containing HCl, then enters an adsorption dechlorination device to adsorb the HCl in the hydrogenated product, and is fed into a rectifying tower to be rectified after the adsorption is finished;

when a hydrodechlorination reactor is started, an alkylation mixed product firstly enters a rectifying tower for rectification, then a tower bottom material of the rectifying tower is introduced into the hydrodechlorination reactor for hydrodechlorination, then is adsorbed by an adsorption dechlorination device, and is introduced into the rectifying tower for 5 minutes to 24 hours after adsorption is finished, the alkylation mixed product is stopped being directly introduced into the rectifying tower, the tower bottom material of the rectifying tower is stopped being introduced into the hydrodechlorination reactor, the alkylation mixed product is directly introduced into the hydrodechlorination reactor, and a normal hydrodechlorination reaction process is carried out;

wherein, a heat exchanger and a gas-liquid mixer are sequentially arranged on a pipeline before entering the hydrodechlorination reactor, the heat exchanger is used for heating an alkylation mixed product, and the gas-liquid mixer is used for fully mixing hydrogen and the alkylation mixed product; the hydrodechlorination adopts a liquid phase reaction state; the hydrodechlorination conditions were as follows: the reaction pressure is 0.5MPa to 6.0MPa, and the reaction temperature is 100 ℃ to 200 ℃.

2. The method of claim 1, wherein: and (3) after adsorption is finished, introducing the mixture into a rectifying tower for 1-10 hours, stopping directly introducing the alkylation mixed product into the rectifying tower, and stopping introducing the tower bottom material of the rectifying tower into a hydrodechlorination reactor.

3. The method of claim 1, wherein: a tower bottom reboiler arranged on the rectifying tower provides a heat source for the rectifying tower, and the rectifying tower bottom material introduced into the hydrodechlorination reactor is led out after the tower bottom reboiler.

4. A method according to claim 3, characterized by: the temperature of the rectification tower bottom material led out after the tower bottom reboiler is 100-200 ℃.

5. The method of claim 1, wherein: the bottom of the rectifying tower is provided with a material conveying device, and the material at the outlet of the bottom of the rectifying tower is conveyed to a pipeline in front of the inlet of the hydrodechlorination reactor through the material conveying device.

6. The method of claim 1, wherein: the gas-liquid mixer is a static mixer or a dynamic mixer, the static mixer is selected from one or a combination of more of an SV type static mixer, an SK type static mixer, an SX type static mixer, an SH type static mixer and an SL type static mixer, and the dynamic mixer is selected from one or a combination of more of a mixing pump, a supercritical mixer and a stirring mixer.

7. The method of claim 6, wherein: a first valve is arranged on a pipeline in front of the gas-liquid mixer.

8. The method of claim 6, wherein: the tower bottom material connecting rectification tower and the first pipeline of the inlet of the heat exchanger are arranged, and the first pipeline is provided with a second valve.

9. The method of claim 7, wherein: and a second pipeline for connecting the inlet of the rectifying tower with the pipeline in front of the first valve is arranged, and a third valve is arranged on the second pipeline.

10. The method of claim 6, wherein: and a third pipeline is arranged for connecting an isobutane outlet of the rectifying tower and an inlet of the gas-liquid mixer, and a fourth valve is arranged on the third pipeline.

11. The method of claim 1, wherein: the hydrodechlorination conditions were as follows: the reaction pressure is 1.2MPa to 3.0 MPa; reaction temperatureIs 120 to 170 ℃; the liquid hourly space velocity is 1.0 h^-1～10. 0h^-1(ii) a The volume ratio of hydrogen to oil is 50: 1 or less.

12. The method of claim 11, wherein: the liquid hourly space velocity is 2.0 h^-1～6.0 h^-1(ii) a The volume ratio of hydrogen to oil is 2: 1-10: 1.

13. the method of claim 1, wherein: the hydrodechlorination catalyst adopts a hydrodechlorination catalyst taking noble metal as an active component, the hydrodechlorination catalyst takes alumina as a carrier and Pt and/or Pd as the active component, and the content of the active component in the catalyst is not less than 0.1% by weight.

14. The method of claim 13, wherein: the content of the active component in the catalyst is 0.1-1.5% by weight.

15. The method of claim 1, wherein: the adsorption dechlorination device is filled with an adsorbent which is an oxide of alkaline earth metal.

16. The method of claim 15, wherein: the adsorbent is calcium oxide and/or magnesium oxide.

17. The method of claim 1, wherein: the adsorption temperature is 100-200 ℃, and the adsorption pressure is 0.5-6.0 MPa.

18. The method of claim 17, wherein: the adsorption pressure is 1.2MPa to 3.0 MPa.

19. The method of claim 1, wherein: at the initial stage of start-up, partial tower bottom materials of the rectifying tower are thrown outwards to obtain the dechlorinated alkylate oil.